1. Field of the Invention
The present invention relates to a testing method of a semiconductor device, and more particularly, to a testing method of a semiconductor device having an embedded nonvolatile memory.
2. Description of the Related Art
A semiconductor device includes various circuits according to uses. The circuits are generally composed of a nonvolatile memory for storing data and a logic circuit having a control function. A tester is used for testing the functions of the semiconductor device. To test the semiconductor device, a test program including a test pattern and a test response is loaded by a user. Then, the semiconductor device is electrically connected to the tester, and the tester having the loaded test program is operated to perform the test for the functions of the semiconductor device. As a result, if the semiconductor device falls under the function requirements, the semiconductor device is considered to have passed the test. If the semiconductor device does not fall under the function requirements, the semiconductor is considered to have failed in the test.
Among a nonvolatile memory included in a semiconductor device, a read only memory (ROM) retains data even if the power is interrupted, once it is masked. Among ROMs, there is an ROM which cannot change data stored therein, which is called a programmable ROM. To test a semiconductor device having an embedded programmable ROM, whenever memory data stored in the programmable ROM, e.g., ROM codes, is changed, the test program must be changed to be loaded in the tester. In the case of testing a semiconductor device having a logic and programmable ROM, the test response for the logic is unchangeable and that for the programmable ROM is changeable according to changing memory data.
Conventionally, whenever the memory data changes, the test program must be generated again. However, in the case of generating the test program whenever the memory data changes, much time is required, which increases the manufacturing cost of the semiconductor device and thus lowers the productivity.